CVE-2026-62823
HIGH 8.8 ALL-YEARSHeap-based buffer overflow in Windows DHCP Server allows an unauthorized attacker to execute code over an adjacent network.
Severe if exploited (CVSS 8.8), but no confirmed exploitation. Patch on a normal cadence.
Exploitation likelihood
0.5%chance of exploitation in 30 days · 45th percentile
Impact if exploited
8.8CVSS 3.1 · HIGH · CNA
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ⚠Access: Must sit on the same / adjacent network
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept
No public PoC is currently catalogued.
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Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.
Affected
Vendors Microsoft
Products Windows Server 2012 Windows Server 2012 (Server Core Installation) Windows Server 2012 R2 Windows Server 2012 R2 (Server Core Installation) Windows Server 2016 Windows Server 2016 (Server Core Installation) Windows Server 2019 Windows Server 2019 (Server Core Installation) Windows Server 2022 Windows Server 2025 Windows Server 2025 (Server Core Installation) Windows 10 1607 Windows 10 1809
Weakness (CWE)
- CWE-122: : Heap-based Buffer Overflow
CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
References and research data (JSON)
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Microsoft | Windows 10 1607 | < 10.0.14393.9418 |
| Microsoft | Windows 10 1607 | < 10.0.14393.9418 |
| Microsoft | Windows 10 1809 | < 10.0.17763.9115 |
| Microsoft | Windows 10 1809 | < 10.0.17763.9115 |
| Microsoft | Windows Server 2012 | < 6.2.9200.26280 |
| Microsoft | Windows Server 2012 | r2 |
| Microsoft | Windows Server 2016 | < 10.0.14393.9418 |
| Microsoft | Windows Server 2019 | < 10.0.17763.9115 |
| Microsoft | Windows Server 2022 | < 10.0.20348.5440 |
| Microsoft | Windows Server 2025 | < 10.0.26100.33222 |
All CVSS metrics
- HIGH 8.8 v3.1 · CNA Primary
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C - HIGH 8.8 v3.1 · NVD Secondary
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
Patches & mitigations
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62823 CVE record · microsoft · Updated 2026-10-21T20:53:56.604Z
NVD · CVE-2026-62823 · Updated 2026-09-02T18:20:55.123
Advisories
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-56675 EUVD · EUVD-2026-56675
Sources: NVD · CVE.org · All sources and attribution · EPSS